# install.packages("remotes")
remotes::install_github("paleolimbot/qgisprocess")

library(qgisprocess)
#> Using 'qgis_process' at '/Applications/QGIS.app/Contents/MacOS/bin/qgis_process'.
#> Run `qgis_configure()` for details.
qgis_configure()
#> getOption('qgisprocess.path') was not found.
#> Sys.getenv('R_QGISPROCESS_PATH') was not found.
#> Trying 'qgis_process' on PATH
#> Error in rethrow_call(c_processx_exec, command, c(command, args), stdin, : cannot start processx process 'qgis_process' (system error 2, No such file or directory) @unix/processx.c:604 (processx_exec)
#> Found 1 QGIS installation containing 'qgis_process':
#>  /Applications/QGIS.app/Contents/MacOS/bin/qgis_process
#> Trying command '/Applications/QGIS.app/Contents/MacOS/bin/qgis_process'
#> Success!

input <- sf::read_sf(system.file("shape/nc.shp", package = "sf"))

result <- qgis_run_algorithm(
  "native:buffer",
  INPUT = input,
  DISTANCE = 1,
  DISSOLVE = TRUE,
  .quiet = TRUE
)
#> Argument `SEGMENTS` is unspecified (using QGIS default value).
#> Using `END_CAP_STYLE = "Round"`
#> Using `JOIN_STYLE = "Round"`
#> Argument `MITER_LIMIT` is unspecified (using QGIS default value).
#> Using `OUTPUT = qgis_tmp_vector()`

result
#> <Result of `qgis_run_algorithm("native:buffer", ...)`>
#> List of 1
#>  $ OUTPUT: 'qgis_outputVector' chr "/var/folders/bq/2rcjstv90nx1_wrt8d3gqw6m0000gn/T//RtmptXCayy/file9b2b462efaa9/file9b2b5212f730.gpkg"

output_sf <- sf::read_sf(qgis_output(result, "OUTPUT"))
plot(sf::st_geometry(output_sf))

qgis_show_help("native:buffer")
#> Buffer (native:buffer)
#> 
#> ----------------
#> Description
#> ----------------
#> This algorithm computes a buffer area for all the features in an input layer, using a fixed or dynamic distance.
#> 
#> The segments parameter controls the number of line segments to use to approximate a quarter circle when creating rounded offsets.
#> 
#> The end cap style parameter controls how line endings are handled in the buffer.
#> 
#> The join style parameter specifies whether round, miter or beveled joins should be used when offsetting corners in a line.
#> 
#> The miter limit parameter is only applicable for miter join styles, and controls the maximum distance from the offset curve to use when creating a mitered join.
#> 
#> ----------------
#> Arguments
#> ----------------
#> 
#> INPUT: Input layer
#>  Argument type:  source
#>  Acceptable values:
#>      - Path to a vector layer
#> DISTANCE: Distance
#>  Argument type:  distance
#>  Acceptable values:
#>      - A numeric value
#> SEGMENTS: Segments
#>  The segments parameter controls the number of line segments to use to approximate a quarter circle when creating rounded offsets.
#>  Argument type:  number
#>  Acceptable values:
#>      - A numeric value
#> END_CAP_STYLE: End cap style
#>  Argument type:  enum
#>  Available values:
#>      - 0: Round
#>      - 1: Flat
#>      - 2: Square
#>  Acceptable values:
#>      - Number of selected option, e.g. '1'
#>      - Comma separated list of options, e.g. '1,3'
#> JOIN_STYLE: Join style
#>  Argument type:  enum
#>  Available values:
#>      - 0: Round
#>      - 1: Miter
#>      - 2: Bevel
#>  Acceptable values:
#>      - Number of selected option, e.g. '1'
#>      - Comma separated list of options, e.g. '1,3'
#> MITER_LIMIT: Miter limit
#>  Argument type:  number
#>  Acceptable values:
#>      - A numeric value
#> DISSOLVE: Dissolve result
#>  Argument type:  boolean
#>  Acceptable values:
#>      - 1 for true/yes
#>      - 0 for false/no
#> OUTPUT: Buffered
#>  Argument type:  sink
#>  Acceptable values:
#>      - Path for new vector layer
#> 
#> ----------------
#> Outputs
#> ----------------
#> 
#> OUTPUT: <outputVector>
#>  Buffered

qgis_algorithms()
#> # A tibble: 986 x 5
#>    provider provider_title algorithm         algorithm_id    algorithm_title    
#>    <chr>    <chr>          <chr>             <chr>           <chr>              
#>  1 3d       QGIS (3D)      3d:tessellate     tessellate      Tessellate         
#>  2 gdal     GDAL           gdal:aspect       aspect          Aspect             
#>  3 gdal     GDAL           gdal:assignproje… assignprojecti… Assign projection  
#>  4 gdal     GDAL           gdal:buffervecto… buffervectors   Buffer vectors     
#>  5 gdal     GDAL           gdal:buildvirtua… buildvirtualra… Build virtual rast…
#>  6 gdal     GDAL           gdal:buildvirtua… buildvirtualve… Build virtual vect…
#>  7 gdal     GDAL           gdal:cliprasterb… cliprasterbyex… Clip raster by ext…
#>  8 gdal     GDAL           gdal:cliprasterb… cliprasterbyma… Clip raster by mas…
#>  9 gdal     GDAL           gdal:clipvectorb… clipvectorbyex… Clip vector by ext…
#> 10 gdal     GDAL           gdal:clipvectorb… clipvectorbypo… Clip vector by mas…
#> # … with 976 more rows