/*
Copyright © 2025 filifa

This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
package cmd

import (
	"errors"
	"fmt"
	"os"

	igraph "scm.dairydemon.net/filifa/gv2adj/cmd/internal/graph"
	idot "scm.dairydemon.net/filifa/gv2adj/cmd/internal/graph/dot"

	"github.com/spf13/cobra"
	"gonum.org/v1/gonum/graph/encoding/dot"
	dotfmt "gonum.org/v1/gonum/graph/formats/dot"
	"gonum.org/v1/gonum/mat"
)

var file string

var matlabFmt bool
var pythonFmt bool

var oneline bool

var weightAttr string

var nodeOrder []string

// rootCmd represents the base command when called without any subcommands
var rootCmd = &cobra.Command{
	Use:   "gv2adj",
	Short: "Compute adjacency matrices for Graphviz graphs",
	Long: `Compute adjacency matrices (either weighted or unweighted) for Graphviz graphs (both directed and undirected).

Compute an unweighted adjacency matrix:
gv2adj -f <dot file>

Compute a weighted adjacency matrix, where weights are stored in the 'len' attribute of each edge:
gv2adj -f <dot file> --weight-attr len
	`,
	// Uncomment the following line if your bare application
	// has an action associated with it:
	RunE: parse,
}

func parse(cmd *cobra.Command, args []string) error {
	data, err := os.ReadFile(file)
	if err != nil {
		return err
	}

	ast, err := dotfmt.ParseBytes(data)
	if err != nil {
		return err
	}

	first := ast.Graphs[0]
	var graph idot.DOTWeightedGraph
	if first.Directed {
		graph = idot.NewDOTDirectedGraph(weightAttr)
	} else {
		graph = idot.NewDOTUndirectedGraph(weightAttr)
	}

	err = dot.UnmarshalMulti(data, graph)
	if err != nil {
		return err
	}

	matrix, err := orderedAdjMatrix(graph.WeightedGraph)
	if err != nil {
		return err
	}

	outputMatrix(matrix)
	return nil
}

func orderedAdjMatrix(g igraph.WeightedGraph) (*mat.Dense, error) {
	matrix := igraph.AdjacencyMatrix(g)
	if len(nodeOrder) == 0 {
		return matrix, nil
	}

	nodeIndexes := make(map[string]int)
	for i := 0; i < len(nodeOrder); i++ {
		nodeIndexes[nodeOrder[i]] = i
	}

	nodes := g.Nodes()
	newOrder := make([]int, nodes.Len())
	for nodes.Next() {
		node := nodes.Node().(*idot.Node)
		id := node.DOTID()

		var ok bool
		newOrder[node.ID()], ok = nodeIndexes[id]
		if !ok {
			return nil, errors.New("node '" + id + "' not found in given order")
		}
	}

	matrix.PermuteRows(newOrder, true)
	matrix.PermuteCols(newOrder, true)

	return matrix, nil
}

func outputMatrix(matrix mat.Matrix) {
	fmtOptions := make([]mat.FormatOption, 0)
	if matlabFmt {
		fmtOptions = append(fmtOptions, mat.FormatMATLAB())
	} else if pythonFmt {
		fmtOptions = append(fmtOptions, mat.FormatPython())
	}

	out := mat.Formatted(matrix, fmtOptions...)

	// for matlab and python formats, %#v outputs as matrix and %v is
	// oneline, but for standard format, it's the opposite, so we xor
	if (matlabFmt || pythonFmt) != oneline {
		fmt.Printf("%#v\n", out)
	} else {
		fmt.Printf("%v\n", out)
	}
}

// Execute adds all child commands to the root command and sets flags appropriately.
// This is called by main.main(). It only needs to happen once to the rootCmd.
func Execute() {
	err := rootCmd.Execute()
	if err != nil {
		os.Exit(1)
	}
}

func init() {
	rootCmd.Flags().StringVarP(&file, "file", "f", "", "dot file")
	rootCmd.MarkFlagRequired("file")

	rootCmd.Flags().BoolVar(&matlabFmt, "matlab", false, "format output as MATLAB array")
	rootCmd.Flags().BoolVar(&pythonFmt, "python", false, "format output as python array")
	rootCmd.MarkFlagsMutuallyExclusive("matlab", "python")

	rootCmd.Flags().BoolVar(&oneline, "oneline", false, "output on one line")

	rootCmd.Flags().StringVarP(&weightAttr, "weight-attr", "w", "", "edge attribute to use as weight")

	rootCmd.Flags().StringSliceVarP(&nodeOrder, "order", "o", nil, "list the graph node names in the order they should be placed in the matrix")
}