// Copyright 2021 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package postgres

import (
	"context"
	"database/sql"
	"fmt"

	"golang.org/x/pkgsite/internal"
	"golang.org/x/pkgsite/internal/database"
	"golang.org/x/pkgsite/internal/derrors"
	"golang.org/x/pkgsite/internal/middleware"
)

// getPackageSymbols returns all of the symbols for a given package path and module path.
func getPackageSymbols(ctx context.Context, ddb *database.DB, packagePath, modulePath string,
) (_ *internal.SymbolHistory, err error) {
	defer derrors.Wrap(&err, "getPackageSymbols(ctx, ddb, %q, %q)", packagePath, modulePath)
	defer middleware.ElapsedStat(ctx, "getPackageSymbols")()
	query := `
		SELECT
			s1.name AS symbol_name,
			s2.name AS parent_symbol_name,
			ps.section,
			ps.type,
			ps.synopsis,
			m.version,
			d.goos,
			d.goarch
		FROM modules m
		INNER JOIN units u ON u.module_id = m.id
		INNER JOIN documentation d ON d.unit_id = u.id
		INNER JOIN documentation_symbols ds ON ds.documentation_id = d.id
		INNER JOIN package_symbols ps ON ps.id = ds.package_symbol_id
		INNER JOIN paths p1 ON u.path_id = p1.id
		INNER JOIN symbol_names s1 ON ps.symbol_name_id = s1.id
		INNER JOIN symbol_names s2 ON ps.parent_symbol_name_id = s2.id
		WHERE
			p1.path = $1
			AND m.module_path = $2
			AND NOT m.incompatible
			AND m.version_type = 'release'
		ORDER BY
			CASE WHEN ps.type='Type' THEN 0 ELSE 1 END,
			symbol_name;`

	sh, collect := collectSymbolHistory(func(sh *internal.SymbolHistory, sm internal.SymbolMeta, v string, build internal.BuildContext) error {
		if sm.Section == internal.SymbolSectionTypes && sm.Kind != internal.SymbolKindType {
			_, err := sh.GetSymbol(sm.ParentName, v, build)
			if err != nil {
				return fmt.Errorf("could not find parent for %q: %v", sm.Name, err)
			}
			return nil
		}
		return nil
	})
	if err := ddb.RunQuery(ctx, query, collect, packagePath, modulePath); err != nil {
		return nil, err
	}
	return sh, nil
}

func collectSymbolHistory(check func(sh *internal.SymbolHistory, sm internal.SymbolMeta, v string, build internal.BuildContext) error) (*internal.SymbolHistory, func(rows *sql.Rows) error) {
	sh := internal.NewSymbolHistory()
	return sh, func(rows *sql.Rows) (err error) {
		defer derrors.Wrap(&err, "collectSymbolHistory")
		var (
			sm    internal.SymbolMeta
			build internal.BuildContext
			v     string
		)
		if err := rows.Scan(
			&sm.Name,
			&sm.ParentName,
			&sm.Section,
			&sm.Kind,
			&sm.Synopsis,
			&v,
			&build.GOOS,
			&build.GOARCH,
		); err != nil {
			return fmt.Errorf("row.Scan(): %v", err)
		}
		if err := check(sh, sm, v, build); err != nil {
			return fmt.Errorf("check(): %v", err)
		}
		sh.AddSymbol(sm, v, build)
		return nil
	}
}