package sqlgen

import (
	"fmt"
	"strings"
)

type schema struct {
	Tables []*table
}

type table struct {
	Name     string // Name in SQL
	Type     string // Go type
	NoInsert bool
	NoUpdate bool
	NoDelete bool
	Columns  []*column
}

type column struct {
	Name     string
	Type     string
	SqlName  string // Defaults to Name
	PK       bool   // PK won't be updated
	NoInsert bool
	NoUpdate bool // Don't update column in update function
}

// ----------------------------------------------------------------------------

func (t *table) colSQLNames() []string {
	names := make([]string, len(t.Columns))
	for i := range names {
		names[i] = t.Columns[i].SqlName
	}
	return names
}

func (t *table) SelectQuery() string {
	return fmt.Sprintf(`SELECT %s FROM %s`,
		strings.Join(t.colSQLNames(), ","),
		t.Name)
}

func (t *table) insertCols() (cols []*column) {
	for _, c := range t.Columns {
		if !c.NoInsert {
			cols = append(cols, c)
		}
	}
	return cols
}

func (t *table) InsertQuery() string {
	cols := t.insertCols()
	b := &strings.Builder{}
	b.WriteString(`INSERT INTO `)
	b.WriteString(t.Name)
	b.WriteString(`(`)
	for i, c := range cols {
		if i != 0 {
			b.WriteString(`,`)
		}
		b.WriteString(c.SqlName)
	}
	b.WriteString(`) VALUES(`)
	for i := range cols {
		if i != 0 {
			b.WriteString(`,`)
		}
		b.WriteString(`?`)
	}
	b.WriteString(`)`)
	return b.String()
}

func (t *table) InsertArgs() string {
	args := []string{}
	for i, col := range t.Columns {
		if !col.NoInsert {
			args = append(args, "row."+t.Columns[i].Name)
		}
	}
	return strings.Join(args, ", ")
}

func (t *table) UpdateCols() (cols []*column) {
	for _, c := range t.Columns {
		if !(c.PK || c.NoUpdate) {
			cols = append(cols, c)
		}
	}
	return cols
}

func (t *table) UpdateQuery() string {
	cols := t.UpdateCols()

	b := &strings.Builder{}
	b.WriteString(`UPDATE `)
	b.WriteString(t.Name + ` SET `)
	for i, col := range cols {
		if i != 0 {
			b.WriteByte(',')
		}
		b.WriteString(col.SqlName + `=?`)
	}

	b.WriteString(` WHERE`)

	for i, c := range t.pkCols() {
		if i != 0 {
			b.WriteString(` AND`)
		}
		b.WriteString(` ` + c.SqlName + `=?`)
	}

	return b.String()
}

func (t *table) UpdateArgs() string {
	cols := t.UpdateCols()

	b := &strings.Builder{}
	for i, col := range cols {
		if i != 0 {
			b.WriteString(`, `)
		}
		b.WriteString("row." + col.Name)
	}
	for _, col := range t.pkCols() {
		b.WriteString(", row." + col.Name)
	}
	return b.String()
}

func (t *table) UpdateFullCols() (cols []*column) {
	for _, c := range t.Columns {
		if !c.PK {
			cols = append(cols, c)
		}
	}
	return cols
}

func (t *table) UpdateFullQuery() string {
	cols := t.UpdateFullCols()

	b := &strings.Builder{}
	b.WriteString(`UPDATE `)
	b.WriteString(t.Name + ` SET `)
	for i, col := range cols {
		if i != 0 {
			b.WriteByte(',')
		}
		b.WriteString(col.SqlName + `=?`)
	}

	b.WriteString(` WHERE`)

	for i, c := range t.pkCols() {
		if i != 0 {
			b.WriteString(` AND`)
		}
		b.WriteString(` ` + c.SqlName + `=?`)
	}

	return b.String()
}

func (t *table) UpdateFullArgs() string {
	cols := t.UpdateFullCols()

	b := &strings.Builder{}
	for i, col := range cols {
		if i != 0 {
			b.WriteString(`, `)
		}
		b.WriteString("row." + col.Name)
	}

	for _, col := range t.pkCols() {
		b.WriteString(", row." + col.Name)
	}

	return b.String()
}

func (t *table) pkCols() (cols []*column) {
	for _, c := range t.Columns {
		if c.PK {
			cols = append(cols, c)
		}
	}
	return cols
}

func (t *table) PKFunctionArgs() string {
	b := &strings.Builder{}
	for _, col := range t.pkCols() {
		b.WriteString(col.Name)
		b.WriteString(` `)
		b.WriteString(col.Type)
		b.WriteString(",\n")
	}
	return b.String()
}

func (t *table) DeleteQuery() string {
	cols := t.pkCols()

	b := &strings.Builder{}
	b.WriteString(`DELETE FROM `)
	b.WriteString(t.Name)
	b.WriteString(` WHERE `)

	for i, col := range cols {
		if i != 0 {
			b.WriteString(` AND `)
		}
		b.WriteString(col.SqlName)
		b.WriteString(`=?`)
	}
	return b.String()
}

func (t *table) DeleteArgs() string {
	cols := t.pkCols()
	b := &strings.Builder{}

	for i, col := range cols {
		if i != 0 {
			b.WriteString(`,`)
		}
		b.WriteString(col.Name)
	}
	return b.String()
}

func (t *table) GetQuery() string {
	b := &strings.Builder{}
	b.WriteString(t.SelectQuery())
	b.WriteString(` WHERE `)
	for i, col := range t.pkCols() {
		if i != 0 {
			b.WriteString(` AND `)
		}
		b.WriteString(col.SqlName + `=?`)
	}
	return b.String()
}

func (t *table) ScanArgs() string {
	b := &strings.Builder{}
	for i, col := range t.Columns {
		if i != 0 {
			b.WriteString(`, `)
		}
		b.WriteString(`&row.` + col.Name)
	}
	return b.String()
}