package cache

import (
	"errors"
	"fmt"

	"golang.org/x/mod/semver"

	"gitea.libretechconsulting.com/rmcguire/git-project-manager/internal/remotes/projects"
)

// Migrations funcs should return errors along with
// number of records updated
type migrationFunc func(c *Cache) (error, int)

// Registry of migrations by version
var migrations = map[string]map[string]migrationFunc{
	"v0.1.0": {
		"Make Aliases Unique": v010_aliases,
	},
}

// Performs any required updates based on version
// of cache read from disk.
// Does not check to ensure migrations were successful,
// only checks if a version has been achieved
func (c *Cache) DoMigrations() (error, int) {
	c.lock.Lock()
	defer c.lock.Unlock()
	return c.doMigrations()
}

func (c *Cache) doMigrations() (error, int) {
	var errs error
	var migrated int
	for version, migrationFuncs := range migrations {
		var funcMigrated int
		if semver.Compare(c.CacheVersion, version) < 0 {
			for name, migration := range migrationFuncs {
				err, numMigrated := migration(c)
				if err != nil {
					errs = errors.Join(
						errs,
						fmt.Errorf("%s - %s: %w", version, name, err),
					)
				}
				funcMigrated += numMigrated
			}

			// We've reached a cache version, update the CacheVersion
			// and write to disk
			if errs == nil && funcMigrated > 0 {
				c.CacheVersion = version
				c.write()
			}
		}
		migrated += funcMigrated
	}

	return errs, migrated
}

func v010_aliases(c *Cache) (error, int) {
	var aliasesMigrated int
	var errs error
	for i, a := range c.Aliases {
		if a.ID == "" {
			if a.Remote == "" {
				errs = errors.Join(errs,
					fmt.Errorf("alias %s [id:%d] has no remote", a.Alias, a.ProjectID))
				continue
			}
			c.Aliases[i].ID = projects.MakeID(a.Remote, a.ProjectID)
			aliasesMigrated++
		}
	}
	return errs, aliasesMigrated
}