/**
 * Copyright (c) 2007-2012, Timothy Stack
 *
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * * Redistributions of source code must retain the above copyright notice, this
 * list of conditions and the following disclaimer.
 * * Redistributions in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer in the documentation
 * and/or other materials provided with the distribution.
 * * Neither the name of Timothy Stack nor the names of its contributors
 * may be used to endorse or promote products derived from this software
 * without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ''AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#ifndef vtab_impl_hh
#define vtab_impl_hh

#include <deque>
#include <map>
#include <memory>
#include <optional>
#include <string>
#include <unordered_set>
#include <vector>

#include <sqlite3.h>

#include "ArenaAlloc/arenaalloc.h"
#include "base/log_level_enum.hh"
#include "base/string_attr_type.hh"
#include "log_format_fwd.hh"
#include "pcrepp/pcre2pp.hh"
#include "robin_hood/robin_hood.h"
#include "sqlitepp.hh"
#include "vis_line.hh"

class textview_curses;

enum {
    VT_COL_LINE_NUMBER,
    VT_COL_LOG_TIME,
    VT_COL_LEVEL,
    VT_COL_MAX
};

class logfile;
class logfile_sub_source;

struct msg_range {
    struct valid {
        bool contains(const vis_line_t vl) const
        {
            return this->v_min_line <= vl && vl < this->v_max_line;
        }

        void expand_to(const vis_line_t vl)
        {
            if (vl < this->v_min_line) {
                this->v_min_line = vl;
            }
            if (vl >= this->v_max_line) {
                this->v_max_line = vl + 1_vl;
            }
        }

        vis_line_t v_min_line;
        vis_line_t v_max_line;
    };

    struct empty_t {};

    using range_t = mapbox::util::variant<valid, empty_t>;

    static msg_range invalid() { return msg_range{{mapbox::util::no_init{}}}; }

    static msg_range empty() { return msg_range{empty_t()}; }

    std::optional<valid> get_valid() const
    {
        if (this->mr_value.is<valid>()) {
            return this->mr_value.get<valid>();
        }
        return std::nullopt;
    }

    bool contains(vis_line_t vl) const
    {
        return this->mr_value.match(
            [vl](const valid& v) { return v.contains(vl); },
            [](const empty_t&) { return false; });
    }

    msg_range& expand_to(vis_line_t vl)
    {
        this->mr_value = this->mr_value.match(
            [vl](valid v) {
                v.expand_to(vl);
                return v;
            },
            [vl](empty_t) { return valid{vl, vl + 1_vl}; });
        return *this;
    }

    msg_range& intersect(const msg_range& rhs)
    {
        if (this->mr_value.valid()) {
            if (rhs.mr_value.valid()) {
                this->mr_value = this->mr_value.match(
                    [&rhs](const valid& v) {
                        return rhs.mr_value.match(
                            [&v](const valid& rv) {
                                return range_t{valid{
                                    std::max(v.v_min_line, rv.v_min_line),
                                    std::min(v.v_max_line, rv.v_max_line),
                                }};
                            },
                            [](const empty_t&) { return range_t{empty_t()}; });
                    },
                    [](const empty_t&) { return range_t{empty_t{}}; });
            }
        } else {
            this->mr_value = rhs.mr_value;
        }

        return *this;
    }

    range_t mr_value;
};

struct log_cursor {
    struct string_constraint {
        unsigned char sc_op;
        std::string sc_value;
        std::shared_ptr<lnav::pcre2pp::code> sc_pattern;

        string_constraint(unsigned char op, std::string value);

        bool matches(const std::string& sf) const;
    };

    template<typename T>
    struct integral_constraint {
        unsigned char ic_op;
        T ic_value;

        static bool op_is_supported(unsigned char op)
        {
            switch (op) {
                case SQLITE_INDEX_CONSTRAINT_EQ:
                case SQLITE_INDEX_CONSTRAINT_IS:
                case SQLITE_INDEX_CONSTRAINT_NE:
                case SQLITE_INDEX_CONSTRAINT_ISNOT:
                case SQLITE_INDEX_CONSTRAINT_GT:
                case SQLITE_INDEX_CONSTRAINT_LE:
                case SQLITE_INDEX_CONSTRAINT_LT:
                case SQLITE_INDEX_CONSTRAINT_GE:
                    return true;
                default:
                    return false;
            }
        }

        integral_constraint(unsigned char op, T value)
            : ic_op(op), ic_value(value)
        {
        }

        bool matches(const T& value) const
        {
            switch (this->ic_op) {
                case SQLITE_INDEX_CONSTRAINT_EQ:
                case SQLITE_INDEX_CONSTRAINT_IS:
                    return value == this->ic_value;
                case SQLITE_INDEX_CONSTRAINT_NE:
                case SQLITE_INDEX_CONSTRAINT_ISNOT:
                    return value != this->ic_value;
                case SQLITE_INDEX_CONSTRAINT_GT:
                    return value > this->ic_value;
                case SQLITE_INDEX_CONSTRAINT_LE:
                    return value <= this->ic_value;
                case SQLITE_INDEX_CONSTRAINT_LT:
                    return value < this->ic_value;
                case SQLITE_INDEX_CONSTRAINT_GE:
                    return value >= this->ic_value;
                default:
                    return false;
            }
        }
    };

    struct column_constraint {
        column_constraint(int32_t col, string_constraint cons)
            : cc_column(col), cc_constraint(std::move(cons))
        {
        }

        int32_t cc_column;
        string_constraint cc_constraint;
    };

    vis_line_t lc_curr_line;
    int lc_sub_index;
    vis_line_t lc_end_line;
    vis_line_t lc_direction{1_vl};

    using level_constraint = integral_constraint<log_level_t>;

    std::optional<level_constraint> lc_level_constraint;
    intern_string_t lc_format_name;
    intern_string_t lc_pattern_name;
    std::optional<uint64_t> lc_opid_bloom_bits;
    std::optional<uint64_t> lc_tid_bloom_bits;
    std::vector<string_constraint> lc_log_path;
    logfile* lc_last_log_path_match{nullptr};
    logfile* lc_last_log_path_mismatch{nullptr};
    std::vector<string_constraint> lc_unique_path;
    logfile* lc_last_unique_path_match{nullptr};
    logfile* lc_last_unique_path_mismatch{nullptr};

    std::vector<column_constraint> lc_indexed_columns;
    std::vector<vis_line_t> lc_indexed_lines;
    msg_range lc_indexed_lines_range = msg_range::empty();

    size_t lc_scanned_rows{0};

    enum class constraint_t {
        none,
        unique,
    };

    void update(unsigned char op, vis_line_t vl, constraint_t cons);

    void set_eof() { this->lc_curr_line = this->lc_end_line = 0_vl; }

    bool is_eof() const
    {
        return this->lc_indexed_lines.empty()
            && ((this->lc_direction > 0
                 && this->lc_curr_line >= this->lc_end_line)
                || (this->lc_direction < 0
                    && this->lc_curr_line <= this->lc_end_line));
    }
};

const std::string LOG_BODY = "log_body";
const std::string LOG_TIME = "log_time";

class log_vtab_impl {
public:
    static const std::unordered_set<string_fragment, frag_hasher>
        RESERVED_COLUMNS;

    enum class provenance_t {
        format,
        user,
    };

    struct vtab_column {
        vtab_column(const std::string name = "",
                    int type = SQLITE3_TEXT,
                    const std::string collator = "",
                    bool hidden = false,
                    const std::string comment = "",
                    unsigned int subtype = 0)
            : vc_name(name), vc_type(type), vc_collator(collator),
              vc_hidden(hidden), vc_comment(comment), vc_subtype(subtype)
        {
        }

        vtab_column& with_comment(const std::string comment)
        {
            this->vc_comment = comment;
            return *this;
        }

        std::string vc_name;
        int vc_type;
        std::string vc_collator;
        bool vc_hidden;
        std::string vc_comment;
        int vc_subtype;
    };

    static std::pair<int, unsigned int> logline_value_to_sqlite_type(
        value_kind_t kind);

    log_vtab_impl(const intern_string_t name)
        : vi_name(name), vi_tags_name(intern_string::lookup(
                             fmt::format(FMT_STRING("{}.log_tags"), name)))
    {
    }

    virtual ~log_vtab_impl() = default;

    intern_string_t get_name() const { return this->vi_name; }

    intern_string_t get_tags_name() const { return this->vi_tags_name; }

    virtual std::optional<std::string> get_command() const
    {
        return std::nullopt;
    }

    const std::string& get_table_statement();

    virtual bool is_valid(log_cursor& lc, logfile_sub_source& lss);

    virtual void filter(log_cursor& lc, logfile_sub_source& lss) {}

    virtual bool next(log_cursor& lc, logfile_sub_source& lss) = 0;

    virtual void get_columns(std::vector<vtab_column>& cols) const {}

    virtual void get_foreign_keys(
        std::unordered_set<std::string>& keys_inout) const;

    virtual void get_primary_keys(std::vector<std::string>& keys_out) const {}

    virtual void extract(logfile* lf,
                         uint64_t line_number,
                         string_attrs_t& sa,
                         logline_value_vector& values);

    virtual bool matches(logline_value_vector& values)
    {
        return false;
    }

    struct column_index {
        robin_hood::
            unordered_map<string_fragment, std::deque<vis_line_t>, frag_hasher>
                ci_value_to_lines;
        uint32_t ci_index_generation{0};
        msg_range ci_indexed_range = msg_range::empty();

        ArenaAlloc::Alloc<char> ci_string_arena;
    };

    std::map<int32_t, column_index> vi_column_indexes;

    void expand_indexes_to(
        const std::vector<log_cursor::column_constraint>& cons,
        const vis_line_t vl)
    {
        for (const auto& cc : cons) {
            this->vi_column_indexes[cc.cc_column].ci_indexed_range.expand_to(
                vl);
        }
    }

    provenance_t vi_provenance{provenance_t::format};
    bool vi_supports_indexes{true};
    int vi_column_count{0};

protected:
    const intern_string_t vi_name;
    const intern_string_t vi_tags_name;
    std::string vi_table_statement;
};

class log_format_vtab_impl : public log_vtab_impl {
public:
    log_format_vtab_impl(std::shared_ptr<const log_format> format);

    virtual bool next(log_cursor& lc, logfile_sub_source& lss);

protected:
    std::shared_ptr<const log_format> lfvi_format;
};

using sql_progress_callback_t = int (*)(const log_cursor&);
using sql_progress_finished_callback_t = void (*)();

struct _log_vtab_data {
    bool lvd_looping{true};
    sql_progress_callback_t lvd_progress;
    sql_progress_finished_callback_t lvd_finished;
    source_location lvd_location;
    attr_line_t lvd_content;
};

extern thread_local _log_vtab_data log_vtab_data;

class sql_progress_guard {
public:
    sql_progress_guard(sql_progress_callback_t cb,
                       sql_progress_finished_callback_t fcb,
                       source_location loc,
                       const attr_line_t& content,
                       bool run_cb)
    {
        log_vtab_data.lvd_looping = true;
        if (run_cb) {
            log_vtab_data.lvd_progress = cb;
            log_vtab_data.lvd_finished = fcb;
        }
        log_vtab_data.lvd_location = loc;
        log_vtab_data.lvd_content = content;
    }

    ~sql_progress_guard()
    {
        log_vtab_data.lvd_looping = true;
        log_vtab_data.lvd_progress = nullptr;
        log_vtab_data.lvd_location = source_location{};
        log_vtab_data.lvd_content.clear();
        if (log_vtab_data.lvd_finished) {
            log_vtab_data.lvd_finished();
        }
        log_vtab_data.lvd_finished = nullptr;
    }
};

class log_vtab_manager {
public:
    using iterator = std::map<string_fragment,
                              std::shared_ptr<log_vtab_impl>>::const_iterator;

    log_vtab_manager(auto_sqlite3& db, logfile_sub_source& lss);
    ~log_vtab_manager();

    using injectable
        = log_vtab_manager(auto_sqlite3&, logfile_sub_source&);

    logfile_sub_source* get_source() { return &this->vm_source; }

    std::string register_vtab(std::shared_ptr<log_vtab_impl> vi);
    std::string unregister_vtab(string_fragment name);

    std::shared_ptr<log_vtab_impl> lookup_impl(string_fragment name) const;

    std::shared_ptr<log_vtab_impl> lookup_impl(intern_string_t name) const
    {
        return this->lookup_impl(name.to_string_fragment());
    }

    iterator begin() const { return this->vm_impls.begin(); }

    iterator end() const { return this->vm_impls.end(); }

private:
    auto_sqlite3& vm_db;
    logfile_sub_source& vm_source;
    std::map<string_fragment, std::shared_ptr<log_vtab_impl>> vm_impls;
};

#endif
