#!/usr/bin/env bash
set -euo pipefail

source_url="${1:-postgresql:///boosapi_migration_test}"
output="${2:-migrations_mysql/20260516000001_initial.sql}"
tmp_dir="$(mktemp -d)"
trap 'rm -rf "$tmp_dir"' EXIT

psql_cmd=(psql -X -qAt -v ON_ERROR_STOP=1 "$source_url")

"${psql_cmd[@]}" -F '|' -c "
SELECT DISTINCT c.relname, a.attname
FROM pg_index i
JOIN pg_class c ON c.oid = i.indrelid
JOIN pg_namespace n ON n.oid = c.relnamespace
JOIN LATERAL unnest(i.indkey) AS key(attnum) ON true
JOIN pg_attribute a ON a.attrelid = c.oid AND a.attnum = key.attnum
WHERE n.nspname = 'public'
UNION
SELECT DISTINCT c.relname, a.attname
FROM pg_constraint con
JOIN pg_class c ON c.oid = con.conrelid
JOIN pg_namespace n ON n.oid = c.relnamespace
JOIN LATERAL unnest(con.conkey) AS key(attnum) ON true
JOIN pg_attribute a ON a.attrelid = c.oid AND a.attnum = key.attnum
WHERE n.nspname = 'public' AND con.contype = 'f';
" > "$tmp_dir/indexed"

map_type() {
  local table="$1" column="$2" data_type="$3" default="$4"
  case "$data_type" in
    bigint) printf 'BIGINT' ;;
    boolean) printf 'TINYINT(1)' ;;
    'double precision') printf 'DOUBLE' ;;
    bytea) printf 'LONGBLOB' ;;
    text)
      if grep -Fxq "$table|$column" "$tmp_dir/indexed"; then
        printf 'VARCHAR(128)'
      else
        printf 'LONGTEXT'
      fi
      ;;
    *) printf 'LONGTEXT' ;;
  esac
}

map_default() {
  local default="$1" data_type="$2"
  [[ -n "$default" ]] || return 0
  if [[ "$default" == nextval\(* ]]; then
    return 0
  fi
  case "$default" in
    '(CURRENT_TIMESTAMP)::text'|'CURRENT_TIMESTAMP'|'now()')
      printf ' DEFAULT (CAST(UTC_TIMESTAMP() AS CHAR))'
      ;;
    true) printf ' DEFAULT 1' ;;
    false) printf ' DEFAULT 0' ;;
    *"::text")
      local literal="${default%::text}"
      if [[ "$data_type" == text && "$literal" == "''" ]]; then
        printf " DEFAULT (CAST('' AS CHAR))"
      elif [[ "$data_type" == text && "$literal" == "'"* ]]; then
        printf ' DEFAULT (%s)' "$literal"
      else
        printf ' DEFAULT %s' "$literal"
      fi
      ;;
    *) printf ' DEFAULT %s' "$default" ;;
  esac
}

{
  echo '-- Generated from the canonical PostgreSQL schema by scripts/generate_mysql_schema.sh.'
  echo '-- Compatible with MySQL 8.0+ and MariaDB 10.6+.'
  echo 'SET NAMES utf8mb4;'
  echo 'SET FOREIGN_KEY_CHECKS = 0;'
  echo

  while IFS= read -r table; do
    echo "CREATE TABLE \`$table\` ("
    mapfile -t columns < <("${psql_cmd[@]}" -F '|' -c "
      SELECT column_name, data_type, is_nullable, COALESCE(column_default, '')
      FROM information_schema.columns
      WHERE table_schema = 'public' AND table_name = '$table'
      ORDER BY ordinal_position;")
    definitions=()
    for row in "${columns[@]}"; do
      IFS='|' read -r column data_type nullable default <<< "$row"
      type="$(map_type "$table" "$column" "$data_type" "$default")"
      definition="  \`$column\` $type"
      [[ "$nullable" == YES ]] || definition+=' NOT NULL'
      if [[ "$default" == nextval\(* ]]; then
        definition+=' AUTO_INCREMENT'
      else
        definition+="$(map_default "$default" "$data_type")"
      fi
      definitions+=("$definition")
    done

    while IFS='|' read -r constraint_name constraint_type column_list; do
      [[ -n "$constraint_name" ]] || continue
      if [[ "$constraint_type" == PRIMARY* ]]; then
        definitions+=("  PRIMARY KEY ($column_list)")
      else
        definitions+=("  CONSTRAINT \`$constraint_name\` UNIQUE ($column_list)")
      fi
    done < <("${psql_cmd[@]}" -F '|' -c "
      SELECT con.conname,
             CASE con.contype WHEN 'p' THEN 'PRIMARY' ELSE 'UNIQUE' END,
             string_agg(format('\\\`%s\\\`', att.attname), ', ' ORDER BY ord.n)
      FROM pg_constraint con
      JOIN pg_class rel ON rel.oid = con.conrelid
      JOIN pg_namespace ns ON ns.oid = rel.relnamespace
      JOIN LATERAL unnest(con.conkey) WITH ORDINALITY ord(attnum, n) ON true
      JOIN pg_attribute att ON att.attrelid = rel.oid AND att.attnum = ord.attnum
      WHERE ns.nspname = 'public' AND rel.relname = '$table' AND con.contype IN ('p', 'u')
      GROUP BY con.conname, con.contype
      ORDER BY con.contype, con.conname;")

    case "$table" in
      api_request_leases)
        definitions+=("  \`active_user_id\` BIGINT GENERATED ALWAYS AS (CASE WHEN \`status\` = 'active' THEN \`user_id\` ELSE NULL END) VIRTUAL")
        definitions+=("  UNIQUE INDEX \`api_request_leases_one_active_per_user\` (\`active_user_id\`)")
        ;;
      agent_runs)
        definitions+=("  \`active_session_id\` VARCHAR(128) GENERATED ALWAYS AS (CASE WHEN \`status\` IN ('starting','running','waiting_approval','waiting_input','cancelling') THEN \`session_id\` ELSE NULL END) VIRTUAL")
        definitions+=("  UNIQUE INDEX \`agent_runs_one_active_per_session\` (\`active_session_id\`)")
        ;;
      payment_refund_requests)
        definitions+=("  \`active_payment_order_id\` BIGINT GENERATED ALWAYS AS (CASE WHEN \`status\` IN ('pending','approved','processing') THEN \`payment_order_id\` ELSE NULL END) VIRTUAL")
        definitions+=("  UNIQUE INDEX \`payment_refund_requests_one_active_per_order\` (\`active_payment_order_id\`)")
        ;;
    esac

    for ((i=0; i<${#definitions[@]}; i++)); do
      suffix=','
      (( i + 1 == ${#definitions[@]} )) && suffix=''
      printf '%s%s\n' "${definitions[$i]}" "$suffix"
    done
    echo ') ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci;'
    echo
  done < <("${psql_cmd[@]}" -c "
    SELECT table_name
    FROM information_schema.tables
    WHERE table_schema = 'public' AND table_type = 'BASE TABLE'
      AND table_name <> '_sqlx_migrations'
    ORDER BY table_name;")

  "${psql_cmd[@]}" -F '|' -c "
    SELECT format(
      'ALTER TABLE \\\`%s\\\` ADD CONSTRAINT \\\`%s\\\` %s;',
      rel.relname,
      con.conname,
      replace(pg_get_constraintdef(con.oid), 'public.', '')
    )
    FROM pg_constraint con
    JOIN pg_class rel ON rel.oid = con.conrelid
    JOIN pg_namespace ns ON ns.oid = rel.relnamespace
    WHERE ns.nspname = 'public' AND con.contype = 'f'
    ORDER BY rel.relname, con.conname;"

  echo
  "${psql_cmd[@]}" -F '|' -c "
    SELECT format(
      'CREATE INDEX \\\`%s\\\` ON \\\`%s\\\` (%s);',
      idx.relname,
      tbl.relname,
      string_agg(format('\\\`%s\\\`', att.attname), ', ' ORDER BY ord.n)
    )
    FROM pg_index i
    JOIN pg_class tbl ON tbl.oid = i.indrelid
    JOIN pg_class idx ON idx.oid = i.indexrelid
    JOIN pg_namespace ns ON ns.oid = tbl.relnamespace
    JOIN LATERAL unnest(i.indkey) WITH ORDINALITY ord(attnum, n) ON ord.attnum > 0
    JOIN pg_attribute att ON att.attrelid = tbl.oid AND att.attnum = ord.attnum
    LEFT JOIN pg_constraint con ON con.conindid = i.indexrelid
    WHERE ns.nspname = 'public' AND con.oid IS NULL
      AND NOT i.indisunique AND i.indpred IS NULL AND i.indexprs IS NULL
    GROUP BY idx.relname, tbl.relname
    ORDER BY tbl.relname, idx.relname;"

  cat <<'SQL'

CREATE UNIQUE INDEX `payment_orders_provider_session_unique` ON `payment_orders` (`provider`, `provider_session_id`);
CREATE UNIQUE INDEX `payment_order_provider_session_unique` ON `payment_order_provider_bindings` (`provider_instance_id`, `provider_session_id`);
CREATE UNIQUE INDEX `payment_order_provider_payment_unique` ON `payment_order_provider_bindings` (`provider_instance_id`, `provider_payment_id`);
CREATE UNIQUE INDEX `payment_refunds_provider_reference_unique` ON `payment_refunds` (`provider_instance_id`, `provider_refund_id`);

SET FOREIGN_KEY_CHECKS = 1;
SQL
} > "$output"

sed -i 's/\\`/`/g' "$output"

for source_migration in migrations/*.sql; do
  name="$(basename "$source_migration")"
  [[ "$name" == "$(basename "$output")" ]] && continue
  [[ -e "migrations_mysql/$name" ]] && continue
  printf '%s\n' "-- Included in the consolidated MySQL/MariaDB initial schema." > "migrations_mysql/$name"
done

echo "generated $output"